T.S. Of Hydrilla
i) Epidermis in the outermost layer composed of single radially elongated compactly arranged chlorenchymatous cells.
ii) Hypodermis is compactly arranged with parenchymatous cells some of which possess chloroplasts.
iii) Cortex is a wide zone covering the space between hypodermis and endodermis; it is composed of aerenchymatous tissue.
iv) Endodermis is the innermost layer of cortex from a row of closely arranged cells that behave as the false endodermis.
v) Pericycle may be distinct as a feeble layer below endodermis or remain indistinct.
vi) Vascular system is reduced protostelic type.
vii) Pith is absent.
Hydrophytic peculiarities
i) Epidermis composed of thin walled chlorenchymatous cells without cuticle
ii) Presence of large air-chambers in the cortical region.
iii) Absence of mechanical tissue.
iv) Vascular system is reduced with only one central xylem cavity surrounded by a wide layer of phloem tissue.
